1. Field of the Invention
This invention relates to offshore oil spill collection devices and particularly to offshore oil spill collection devices that operate below the surface of the sea to collect oil and gas.
2. Description of the Prior Art
Damage to the environment by leaking oil or gas from underwater pipelines or oil wells has become a serious problem. Costs to remove oil coming to the surface via these leaks from an underwater well or pipeline are tremendous. In addition, the loss of the oil can be in hundreds or thousands of barrels a day, which is a significant loss of a vital natural resource. Recent events in the Gulf of Mexico illustrate the extent and seriousness of this problem.
The main techniques for dealing with such leaks or spills have been removing the oil from the surface of the water and land, and cleaning wildlife. However, simply cleaning up the oil is not sufficient to prevent or reduce the loss of a vital natural resource. In the recent Gulf spill, millions of gallons of oil were burned off or simply disbursed into the sea, where they may be accumulating on the sea floor.
In addition to oil leaks, there are natural methane and oil seeps located below the surface of the sea. Such seeps can provide a source of gas and oil, while the recovery of such gas helps control the emission of a greenhouse gas into the environment.
Oil recovery apparatus can be effective in preventing the contamination caused by oil and oil/gas leakage from underwater pipelines or oil wells. For example, a large number of oil wells are located offshore in deep water and rupture of a well casing, etc., causes the oil/gas to be discharged upwardly under pressure from the oil well, resulting in a loss of oil. Presently, there are few devices that are used to collect leaked or spilled oil from the sea. One such device is found in U.S. Pat. No. 5,213,444 to Henning. This device is a housing that is positioned above an underwater leak and anchored in place. As the oil and gas rise in the water column, the device can trap the oil and gas within the housing. The device has a vent with a burner that can be used to burn off the gas. It also has a pump to remove the oil that is collected. Although this device seems to be a good solution, it has several problems. First, the device must be positioned so that the top of the housing is above the water. This is to allow the gas to be burned off and the oil to be pumped onto barges or other vessels. However, it is difficult to maintain such a device in such a position because of currents, wave action and storms. Moreover, in many cases the oil pipelines or wells are at great depths (the gulf well in the recent spill was over a mile deep). A column of oil rising from that great a depth will be dispersed by currents and wave action long before it breaks the surface. Even a large number of such devices placed on the surface will only collect minor amounts of such oil.
At present, there is no such device for capturing such gas and oil from undersea seeps. Therefore, there is a need for a collection system that can operate under the surface so that it can be positioned to collect both leaking and seeping oil and gas from the sea floor.